The Militia is loosely divided into brigades. Each brigade is responsible for fighting in an assigned section of Frontier territory, which might span as far as several planetary systems. The Marauder Corps, a.k.a. the M-COR, is a small part of a much larger brigade tied to the Freeport System. Although some brigades are little more than vast pirate organizations, the Militia has enough resources to be a real obstacle to the IMC's ambitions on the Frontier.
The Militia often claims that direct action against the IMC is in the best interests of the homesteaders whom they allegedly represent, but not everyone on the Frontier sees it that way.